Multiple-transfer switchboard.



PATENTED JAN. 3, 1905.

C. B. SMITH. MULTIPLE TRANSFER SWITGHBOARD.

APPLICATION FILED MAY 8. 1900.

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0. B. SMITH. MULTIPLE TRANSFER SWITGHBOARD.

APPLIUATION FILED MAY 8. 1900.

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UNTTED STATES Patented. January 3, 1905.

CHARLES B. SMITH, OF NEW YORK, N. Y.

MULTIPLE-TRANSFER SWITCHBOARD.

SPECIFICATION forming part of Letters Patent No. 779,004, dated January 3, 1905.

Application filed May 8,1900- Serial No. 15,883.

To alt whom it may concern.-

Be it known that 1, CHARLES B. SMITH, a citizen of the United States, residing in New York city, borough of Manhattan, State of New York, have invented certain new and useful Improvements in Multiple-Transfer Switchboards,of which the following is a specification.

The main object of my invention is to provide a switchboard system for telephone-lines wherein a plurality of sections of the board are each associated with sets of trunk-lines or conductors, each set embracinga test-line, each section having one or more sets of such lines normally apportioned to it. Circuit controlling and indicating devices are associated with the test-lines'to indicate the busy and idle lines that are apportioned to either section, whereby an operator at one section can test trunk-lines that are normally apportioned to any other section, so as to be able to readily ascertain which of such lines is idle to enable desired connections to be made be- Switching apparatuses are provided at each section, whereby an operator at one section can connect a pair of local subscribers circuits and can also connect a local subscribers circuit with any of the trunk-lines associated with other sections of the board, and in carrying out my invention 1 also provide each section with appropriate circuit controlling and indicating devices whereby an operator can readily ascertain when a subscriber has finished using a line and can also conveniently communicate with an operator at a section on either set of trunk-lines.

The invention further consists in the novel details of improvement that will be more fully hereinafter set forth and then pointed out in the claims.

In the accompanying drawings, Figure 1 is a diagrammatic view of a multiple-transfer switchboard system embodying my invention, and Fig. 2 is a diagrammatic view more fully illustrating the switching and indicating devices I have provided for use in conjunction with a switchboard, more particularly illustrating at one section the switching devices for connecting two local subscribers lines or a local subscribers line with a trunk-line and another section illustrating the connections whereby one operator is enabled to receive instructions from another operator, a local subscribers circuit also being illustrated in connection with such section.

In the accompanying drawings similar letters and numerals of reference indicate corresponding parts in the different views.

At a central ofiice are located sections of a switchboard, as A B C, and between these sections extend sets of trunk-lines or conductors, as 1 2 3 4 5 6, each set of trunk-lines comprising a pair of lines, as l 1, for a metallic telephone-circuit, and an independent line, as 1 for a test-circuit. One or more sets of such trunk-lines are apportioned to each section of the switchboard. For instance, the sets 1 and 2 are shown apportioned to section A, sets 3 and A to section B, and the sets 5 and 6 to C, or, in other words, those sets of lines are respectively normally connected with the receiver of the corresponding section. The sets of trunk-lines that are apportioned to a section are at each other section associated with multiple jacksas, for instance, at section A jacks a a are connected with the sets of trunk-lines 3 4 and jacks (6 66 are connected with lines 5 6, that are apportioned to B and C, respectively. At section B the jacks b b are connected with the sets of lines 1 2 and the jacks 6 Z) are connected with lines 5 6 of sections A and C, and the jacks c c at section 0 are connected with the sets of lines 1 2 and the jacks c 0 are connected with lines 3 4 of sections A and B. Each of these jacks has associated with it a metallic ring or contact d, that is connected with the test-line of the corresponding set of trunk-lines. A contact c is adapted to engage the corresponding ring or contact d, and the contact a is normally connected to ground through a lamp or other indicating instrument, as f. Any suitable means may be provided for closing the circuit between eand d. I have shown springcontrolled push-rods g each adapted to control the contacts a that are at each section associated with the multiple jacks of the trunklines which are apportioned, respectively, to other sections. It will be understood that when the operator pushes a rod 9 circuit will be closed from ground through lamp f over a test-circuit, and if the corresponding set of trunk-lines is in use the operator will be ap prised of that fact, so that she can bring into use through the multiple jack the set of trunklines of the desired section that are idle, and this notice to the operator can be given either by producing a lighter other signal on the busy line or on the idle line. I have shown an arrangement whereby a light will be indicated on a busy line, as will be more fully hereinafter explained. It will be understood that when an operator at a section ascertains that a set of trunk-lines apportioned to a desired section are idle she will place a plug in the multiple jack at her section that is connected with such set of idle trunk-lines and that by a proper manipulation of a switch or key said operator can place herself in communication with the operator of the desired section to instruct the latter operator which subscriber connected with that operators section is desired.

At each section a suitable number of local subscribers lines are connected with jacks, and the operator at each section has switching apparatus adapted to be connected with the jacks of the local or subscribers lines and with the multiple jacks of the trunk-lines, and in the switching apparatus which I have illustrated means are provided to enable an operator to receive a communication from a calling subscriber to call and converse with a subscriber connected with the same section and to connect such subscriber with any other section, and in these devices-1 provide means for indicating when one or both subscribers have finished using a line. I will first describe how an operator receives a call and makes connection between two subscribers connected with her section and will then explain how the operator connects a subscriber of her section with a subscriber at any other section.

In Fig. 2 I have shown a set of trunk-lines, as 3, which are normally apportioned to section B, illustrating at B merely those devices that enable an operator to receive instruction andconnect her switching apparatus with a subscriber associated with her section, and at section A are illustrated in detail the switching devices that enable an operator to effect the necessary calls, answers, and connections with subscribers at her section and to connect such subscribers with the trunk-lines not apportioned to such switches. At each section any desired number of jackslO are located and connected with lines 11, leading to a substation, as A B C, at which are located any suitable telephone and call-receiving instruments. At the sections each subscribers line 11 is provided with an indicating instrument, such as an annunciator-drop12, which I have shown connected to ground through a battery and a conductor 13, that is shown bridged across the springs of jack l0, and thus normally in circuit with lines 11. At the subscribers stations the limbs of lines 11 terminate, respectively, at contacts 11 11 normally out of contact with but adapted to be engaged by contact 14:, insulated from but controlled by the hook 14 of receiver 15. The contact 14 is also connected to ground, and thus when the receiver is removed from its hook circuit will be established from a subscriber to the indicator 12 at central over the two limbs of line 11 to ground at central, including the battery, thus operating the indicator to give a signal at central; At the subscribers station is located a signaling instrument 16, with which a contact 16 is connected, and normally in circuit with hook 14 when the receiver is upon said hook, which instrument 16 is also connected with one side of the line 11, whereby a call can be received at a station over line 11. At the section of the switchboard a contact or ring 17 is located in line with jack 10 and connected to ground through a battery 18, 17 being a guide-ring for the plug. A plurality of the rings 17 may be connected to the same battery and ground, as in Fig. 2.

The switching apparatus for the operator comprises strands 2O 21 of a plug-cord circuit, with which an answering-plug 22 is connected through a normally closed switch or key 23, one spring of which is connected to the tip and the other spring to the sleeve of plug 22, and a calling-plug 24:, which is connected with a normally closed switch or key 25, the tip of said plug being connected with one spring of said switch and the sleeve of said plug being connected with the other spring thereof. The switches 23 25 are adapted to close normally open generator-circuits 27 for calling when the plug is placed in a suitable jack.

28 is a battery, shown bridged across the strands of the plug-cord circuit. The operators telephone-receiver 29 is normally out of circuit with battery 28, but is'adapted to be thrown into circuit with either plug 22 or 24, as desired, by a switch or key 30. For this purpose I have shown pairs of contacts controlled by said switch. The contact 31 is connected by conductor 31 with strand 20 between battery 28 and plug 22, and the contact 32 is likewise connected by conductor 32 with strand 21 between said battery and plug. One terminal of receiver 29 is connected with a contact 29, adapted to be engaged by contact 31, and the other terminal of said receiver is connected with acontact 29, adapted to be engaged by contact 32. Thus when switch 30 is moved to the right in Fig. 2 the receiver 29 will be thrown in circuit with the plug 22, so that when the operator places said plug in jack 1O andswings switch 30 to the right she may converse with a subscriber. Switch 30 likewise controls the circuit of receiver 29 I through plug 2 1, and for this purpose I have shown a contact 33 connected with a contact normally in circuit with one spring of switch and a contact 34 normally-connected with the other spring of said switch, and the strand 20 leads to a contact 35 in normal engagement with contact 33, while the strand 21 leads to a contact 36 in normal engagement with contact 34, the circuit through cord-circuit 2O 21 being adapted to be broken when switch is thrown to the left in Fig. 2, whereupon contacts 33 and 34 will be moved, respectively, into engagement with contacts 37 and 38, connected, respectively, with the opposite terminals of receiver 29. Thus when one operator desires to communicate with another operator, plug 24 will be placed in the appropriate multiple jack connected with the set of trunk-lines that are apportioned to the section desired and switch 30 will be thrown to the left in Fig.

2, which breaks the plug-cord circuit to the right and places the receiver 29 of the calling operator in circuit with the receiver at the desired section, so that instruction may be given to the operator thereat. Plug 24 is used in a jack 10 of a called subscriber or in a multiple jack of a'set of trunk -lines to communicate with an operator at a desired switchboard. Each trunk-line at its respective section terminates in a plug 70, whose tip and sleeve ll 71 connect with the telephone-lines, and the plug has an additional sleeve 7L3, that is connected by a conductor with the test-line of that trunk-line, and said sleeve is adapted to engage the ring or contact 17 of the corresponding jack 10 of a subscribers line, whereby circuit to ground through battery 18 can be -established. One terminal of the receiver 29 is also connected by a contact of a switch 40 with a contact 41, connected with said tele phone-line. The other telephone-line is connected by a contact 42 with a contact of switch 40 that leads to the opposite terminal of receiver 29. Circuit through the receiver 29, switch 40, and contacts 41 42 is normally maintained established, preferably, through the medium of plug it, which when inserted in a suitable socket bears against a lever or other suitable device 43, which operates an insulated plug 44, adapted to hold the contacts of switch 40 in engagement with contacts 41 and 42; but when plug /& is removed from its socket the spring of lever 43 moves said plug 44, whereupon switch 40 will break the circuit of the receiver at 41 42, and thus the receiver is cut out of circuit with plug it; but the sleeve and tip of said plug remain in circuit with the telephone-lines and said plug can thereupon connect said telephone lines through jack 10 with a subscribers line 11.

It is designed that if a set of trunk-lines of one section is in use by a subscriber a signal may be given to an operator at another section to indicate that fact, as before stated, and the arrangements I have shown are such that a light will glow upon the operation of a push-rod y if either set of lines connected therewith is in use. This is accomplished through the medium of sleeve [L in connection with contact or ring 17, as follows: If plug it is in a jack 10, sleeve 71 will be in circuit with ring or contact 17 andthereupon when a push-rod g is operated which is associated with the trunk-lines to which that plug it is apportioned circuit will be closed at (Z c, and thereupon current will flow from ground at the calling-section through lamp f and over the test-conductor, as 3 in Fig. 2, to the sleeve [b3 at B and through 17 and 18 to ground, whereupon at the calling-section the lampfwill glow and indicate that that particular set of trunklines is in use; but if any other set of trunklines associated with that push-rod g were not in use circuit would not be found for the lamp, and thereupon the calling operator would insert plug 24 in the proper multiple jack. It is also intended that a signal will be given at a called section when the operator at a callingsection removes her plug 24 from a multiple jack to indicate to the operator at a called section to remove her plug it from jack 10. This is accomplished as follows: 45 is a relay on the conductor leading from the test-line to sleeve [L3, the armature of which relay is adapted to control a local indicating-circuit, shown provided with a lamp 46 and battery 47, in which local circuit is a contact 48, normally out of engagement with a contact 49, but adapted to be thrown into engagement therewith when plug b is removed from its socket and lever 43 moves plug 44 to break the circuit of receiver 29, and thereby contact 48 is thrown into engagement with contact 49 and closes the local circuit. The lamp 46 will be temporarily lighted while plug it is being removed from its socket and placed in jack 10, but will be extinguished by the breaking of the local circuit, caused by magnetization of relay 45 over a circuit established at the calling-operators section, as follows: The sleeve 24 at the calling-section is adapted to make contact with ring or contact (Z, and said sleeve is connected bya conductor 50 with a contact 51, leading to ground, so that while plug 24 is in a multiple jack at a calling-section circuit will be established from ground through 51, 50, 24 and (Z at the last-named section over the test-line to the desired section through relay 45, sleeve 71 contact 17, battery 18, to ground, whereby the local circuit of lamp 46 will be maintained broken by relay 45. When the calling operator removes plug 24 from the jack, the circuit of relay 45 will be broken and the lamp 46 will indicate to the called operator that she should remove plug from jack 10. It is also designed to give a signal to the calling operator that will enable her to determine that plug it is in jack 10 at a called section, and this is accomplished as follows: The contact 50 of conductor 50, which is in normal engagement with contact 51, is adapted from ground through 53, 52, 50, 50, sleeve 24, and ring or contact d at the calling-section and over the test-circuit to the called section and through the plug it, contact 17, and battery 18to ground thereat. Thus by moving switch 30 to the left at any time an operator can determine Whether or not a plug /t at another section is in circuit with a called subscriber, because if said plug is in circuit signal 53 will indicate that fact.

I have provided means for indicating to an operator when a subscriber, on a local. circuit connected with her section hangs up his receiver 15, and for this purpose I provide a conductor 55 and a relay-controlled circuit 56, which circuit is provided with a lamp or other indicating instrument 57, the relay 58 being connected with strand 20. There may also be a lamp or indicating instrument 59 in circuit with said conductor 55 and controlled by a relay 60, connected with strand 20, said relays 58 and 60 being on opposite sides of battery 28. Conductor 55 is connected with a contact 61, normally out of engagement with a contact 62, which is connected with a battery 63 and ground, and plug 22 when in a suitably-arranged socket rests upon a lever 64 or other suitable device, whereby circuit is normally broken at 61 62. When plug 22 is removed from its socket, the circuit of the lamps 57 59 will be closed at 61 62; but when plug 22 is in a jack 10 and the receiver at a called station is removed from its hook the closed circuit in the plug-cord will cause relay 58 to break the circuit of lamp 57, and likewise when the calling-plug 24 is placed in circuit with a jack 10 and the receiver connected with the corresponding line is removed from its hook relay 60 will break the circuit of light 59. As soon as either subscriber hangs up his receiver 15, the circuit of the plug-cord being then through the high-resistance bell 16, the relay 58 or 60 will enable the circuit of the lamp 57 or 59 to be reestablished. I have shown magnets 65 66 on the strands of the plug-cord circuit opposite the relays 58 60, which may serve to balance the circuit.

The operation of my improvements may be described as follows: First, assume that a subscriber connected with a section, as A, desires to converse with another subscriber connected with the same section. The subscriber signal.

plug 22 from its socket and places it in jack 10, which breaks the circuit of instrument 12, and the circuit of conductor 55 is closed at 61 62, and she then throws switch 30 to the right in Fig. 2, thus bridging her receiver 29 across the plug-cord circuit and inquires what is wanted. During this time relay 58 breaks the circuit of instrument or lamp 57. Upon learning the desired connection she restores switch 30 to its normal position and places plug 24 in jack 10 of the desired subscriber and operates switch 25, which causes the generator to produce a call at the desired station, and until the subscriber responds instrument or light 59 will operate, because the plug-cord circuit for relay 60 is not yet established at book 14 at the called station through the low-resistance receiver. As soon, however, as the called subscriber removes receiver 15 from its hook relay 60 will break the circuit of instrument 59, and both lights will be out. When one or both subscribers hang their receivers upon the hooks 14, the relay or relays 58 60 will be deenergized and the instruments 57 and 59 will indicate a clearing-out signal. The operator thereupon removes plugs 22 and 24 from the jacks 10 and places said plugs in their sockets, thus opening the local clearing-out or light circuit again. Next assume that a subscriber associated with one section, as A, desires to communicate with a subscriber associated with another section,as B. The subscriber, as at A, removes his receiver from its hook and produces a signal at instrument 12, as before stated, and the operator at A places plug 22 in the appropriate jack 10 and inquires what is wanted, whereupon light 57 will be extinguished. The operator next tests the sets of trunk-lines that are apportioned to section B, as by pushing-rod 9, connected with the multiple jacks a at. If one or more of said sets of trunk-lines are idle, the light or lights f will not glow. Let it be assumed that the set of trunk-lines 3 are idle. The operator atA either before or after testing the trunklines moves switch or lever 30 to the left in Fig. 2, which breaks the cord circuit to the right, and she places her receiver in circuit with her calling-plug 24 and inserts said plug in the appropriate jack, as a, whereupon the receiver 29 at the calling and called sections will be in circuit, and the operator at A instructs the operator at B to place her plug it in the jack 10 of the desired subscriber. The operator at B removes plug h from its socket and places it in theappropriate jack 10, and the lever 43 thereupon breaks the circuit of receiver 29 at 40 41 42 at section B over the circuit leading from the selected set of trunklines, as 3. Circuit to ground through battery 18 is now established for instrument 58 at the calling-section, from ring or contact 17 to relay 45 atB over the test-line, through cl, 24, contact 52, and instrument 53 to ground, (because switch 30 is still, held to the left in Fig. 2,) which indicates at 53 to the operator at A that plug 7: is in a jack 10 at B. Relay 45 at B thereupon breaks thelocal circuit of light 46. The operator at A restores switch 30 to its normal position and operates switch 25 to produce a call over the connected trunkline at the station, as B, that has been connected with the jack 10 of B. The subscribers associated with two sections are now in telephonic connection through the plug-cord circuit and a trunk line normally apportioned to the called switchboard. When a subscriber hangs his receiver upon its hook, a corresponding light 57 or 59 will glow, as before explained, and when the operator at A removes calling-plug 24 from the multiple jack the light 46 at the called section will glow, as its local circuit is now closed, (at 48 49, the relay 45 being deenergizech) which indicates to the operator at section B a clearing-out signal, whereupon she removes plug It from jack 10 and places said plug in its socket. Plug 44 moves to break the circuit of light 46 and establish the normal circuit of receiver 29 at 40 41 42.

I do not limit my invention to the precise details of improvement shown and described, as they may be varied without departing from the spirit thereof.

Having now described my invention, what I claim is 1. In a switchboard, a plurality of sections, a plurality of metallic-circuit trunk-lines each terminating at a section in a plug, a receiver normally bridged across said trunk-lines, and switching devices at each section associated with the trunk lines of the other sections adapted to establish telephonic communication with said receiver.

2. In a switchboard, a plurality of metalliccircuit trunk-lines extending between the sections thereof, one or more of said trunk-lines terminating in a plug at each section, a receiver normally bridged across said trunklines, a plurality of subscribers circuits terminating at each section to be connected by said plug with the corresponding trunk-lines, a plurality of jacks, the other trunk-lines at each section being connected with said jacks, and switchingapparatus at each section adapted to connect a subscribers circuit with the "jacks thereat.

3. In a switchboard, a plurality of sets of trunk-lines, each set comprising telephonelines and a test-line, a plug at each section, the lines of one or more sets at each section being connected with a plug, a plurality of jacks, and the lines of the other sets at said section being connected with jacks, means at each section for establishing the circuit for the corresponding test line by the corresponding plug, means at each section associated with each jack to test the circuit of the corresponding set of trunk-lines, and switching apparatus at each section to connect a jack with a subscribers circuit leadingfrom said section. 4. In a switchboard, a plurality of sets of trunk-lines, each set comprising telephonelines and a-test-line, plugs and a receiver at each section, the lines of one or more sets at each section being connected with said plug and receiver, jacks, and the lines of the other sets at said section being connected with said jacks for establishing the circuit of the corresponding test-line by the corresponding plug, contacts at each jack associated with the corresponding test-line and connected with a signaling instrument to indicate which trunklines are in use when the circuit is closed by said contacts, and switching apparatus at each section for connecting a jack with a subscribers circuit.

5. In a switchboard, a plurality of sets of trunk-lines extending between the sections thereof, a plug and a receiver at each section, one or-more of said sets of trunk-lines being each in circuit with said plug and with said receiver at a section, means for establishing a circuit for the corresponding test-line, other sets of trunk-lines at such section being connected with jacks, and switching apparatus at each section to connect with said jacks and comprising a signaling instrument and its circuit adapted to be operated over the test-line when the plug at another section has established a circuit for said test-line.

6. In a switchboard, a plurality of sets of trunk-lines extending between the sections thereof, two lines of a set at a section terminating in a plug and the test-line of the set being adapted to be connected to ground, jacks at the sections, the phone-lines of said sets of lines being connected at the other sections with such jacks and the test-line being connected with a contact thereat, and switching apparatus at the sections comprisinga plug adapted to engage a jack and having acontact to engage the contact of the corresponding test-line, a signaling instrument and circuit associated with said contact of said plug, and means for establishing the circuit of said signaling instrument to indicate that the plug of a called operator has been connected with a subscribers circuit at the called section.

7 In a switchboard, a plurality of sets of trunk-lines normally apportioned to a section, each set having a test-line and means to establish the circuit of its test-line, and a signaling instrumentassociated with the same set at each other section, and means to complete the circuit of the test-line through said signaling instrument.

8. In a switchboard, a plurality of sets of trunk-lines extending between the sections, one or more sets of trunk-lines terminating at each section in a plug and a receiver, the testline of the corresponding set being connected with a contactof said plug, a signaling instru- LOO ment associated with said plug and controlled by current on the test-line, means at each section for establishing a circuit through said contact, and switching apparatus at each section for connection with the trunk-lines of the other sections and comprising a plug having a contact normally connected to ground and adapted to control the circuit of the signaling instrument of another section to indicate a clearing-out signal when said plug has been removed from a trunk-line jack.

9. Ina switchboard, a plurality of sets of trunk-lines extending between the sections thereof, one or more sets of trunk-lines being connected at a section with a plug and witha receiver, and connected at the other sections with a jack and contact, a signalinginstrument associated with each of said plugs and its circuit maintained normally broken by the corresponding plug, the circuit of said instrument being closed when said plug is in a jack of a subscribers circuit, a relay connected with the corresponding test-line to control the circuit of the signaling instrument, and switching apparatus at each section having a contact to connect with the test-lines, said contact being normally connected to ground to maintain the circuit of the signaling instrument at ancircuit with the plug-cord circuit on either side of the battery.

11. In a switchboard, a plurality of sets of trunk-lines extending between the sections theroof, and each set comprising a pair of telephone-lines and a test-line, a plug at each section, one or more telephone-lines being connected at each section with such a plug, the corresponding test-line being also connected with said plug, means for establishing a circuit for the test-line through said plug, a plurality of jacks at each section, said trunk-line being connected with the jacks at the other sections, and means associated with said jacks for testing said trunk-lines.

CHAS. B. SMITH.

WVitnesses:

A. R. ANGUS, T. F. BOURNE. 

